Recently, as shown in the patent document 1, an LED that is superior to a halogen light source in stability of light intensity, a life duration and a fast response characteristic and that can be downsized with low heat generation has been used for a light source of this kind of light irradiating device.
Especially, for the light irradiating device referred to as a spot light irradiating device intended to emit light of the illumination intensity that is even as much as possible on a certain area, with the intention of making the light, emitted from the LED and whose light intensity is uneven, in a state of even surface emission, a columnar light transmission element referred to as a rod lens is arranged inside a distal end of a casing and the light emitted from the LED is made to pass through the rod lens so as to reduce the unevenness in the light intensity and then the light is emitted outside.
At this time, since it is necessary to condense the light emitted from the LED on a light introducing face as being a proximal end face of the rod lens, the inventor of this invention is now developing a light condensing lens that enables substantially all of the light emitted from the LED to emit in front by providing an additional reflection surface around the LED.    Patent document 1: Japan Patent Laid-open number 2003-240721